Full-colour switching in graphene-based Fabry-Perot nanocavities actuated by intercalation

Abstract

Abstract Graphene-based electro-optical materials have revolutionized optoelectronics by enabling multispectral and energy-saving tunability. However, the colour gamut of these compounds is too narrow to achieve acceptable visual aesthetics for future electrochromic applications. Here, we have achieved a major advancement by creating graphene-based Fabry-Perot nanocavities-type electrochromic supercapacitors that can be tuned to different colours. By manipulating the optical indexes (n, k) of the multilayer graphene through lithium-ion intercalation/de-intercalation, we were able to achieve optical reflectivity manipulation in the visible region. Furthermore, the energy consumption for the proof-of-concept display device is around 1.59 mW cm− 2, one-tenth of that of commercial organic light-emitting displays. Additionally, the pixel size of the Fabry-Perot nanocavity-type electrodes can be reduced to 2 µm, less than half the size of current displays like Micro-LED. Our findings provide a pathway towards nearly-zero-energy-consumption full-colour displays and also inspire further research in active photonics with low power consumption across a wider range of applications.